1. Field of the Invention
The present invention relates to a CCD (Charge Coupled Device) type solid-state image pickup device and a method of manufacturing the same, and an image pickup device.
2. Description of the Related Art
Progress is being made in increasing an angle of view of the CCD type solid-state image pickup device and in miniaturization of pixels of the CCD type solid-state image pickup device. The opening area of light receiving units of the pixels is decreased, so that to improve the sensitivity characteristics of the pixels is a great challenge.
The CCD type solid-state image pickup device has a plurality of light receiving units arranged in the form of a matrix. A transfer channel and a plurality of transfer electrodes for reading a signal charge accumulated in a light receiving unit and transferring the signal charge in a vertical direction are provided between light receiving units adjacent to each other in a horizontal direction. The transfer electrodes are coupled to each other by wiring passing in the horizontal direction over a part between light receiving units in the vertical direction. Because the transfer electrodes themselves block light incident on the light receiving units and thereby cause a decrease in sensitivity of the pixels, a structure for reducing the thickness or projection parts of transfer electrodes has been proposed.
As a structure for reducing the projection parts, a so-called single-layer type transfer electrode structure in which all transfer electrodes are formed by one-time formation of film of polysilicon has been proposed instead of a conventional vertical CCD structure in the past in which transfer electrodes are formed by two layers or three layers of polysilicon which is disclosed in Japanese Patent Laid-Open No. 2003-60819, for example.